FIG. 7.

Type II collagen immunostaining of hMSC cultured in PEG gels of different compositions. hMSC cultured in nondegradable PEG gels without adhesion peptides (No peptide–Non Deg, A), nondegradable PEG gels with RGD peptides (RGD–Non Deg, B), nondegradable PEG gels with GFOGER peptides (GFOGER–Non Deg, C), degradable PEG gels without peptides (No peptide–Deg, D), degradable with RGD peptides (RGD–Deg, E), and degradable with GFOGER peptides (GFOGER–Deg, F). All hydrogels were cultured for 21 days in chondrogenic medium. Images were acquired with a 40× objective. Color images available online at www.liebertpub.com/tea